Which motor for an effective pusher?

[bbot]

Hi!
I will be building my first antweight: a pusher. For wheels, I'll be using 4 Fingertech Mini Sumos. They're quite wide and should provide good grip. So my question: What's the right mini gear motor motor (4x) to choose for max usable traction? Also, since I'm a beginner, I don't want it to run too fast... I was thinking about a 100:1 maybe?

[haz]

100:1 on (what I think) are quite small wheels would be too slow. I'd say 50:1 would be better, probably the HP versions.

Welcome to the forum

[EpicentrE]

You can use my spreadsheet to work out the speeds of motor/wheel combinations: https://docs.google.com/spreadsheet/ccc ... sp=sharing

Just put your voltage and wheel diameter in at the top and it will tell you all the information you require.

For a pusher ant, I'd recommend 1m/s as a minimum, but more is a good thing as long as you can control it. If you can't control it, you'll just end up flying off .

I echo the recommendation for the Pololu HP motors - they give the best power to weight ratio out of all 12mm gearmotors I've found. If you're using the 28.6mm diameter wheels, and a 3-cell lipo then you can go for the 100:1 (1m/s) or the 50:1 (2m/s). If you're using a 2-cell lipo, then you can go for the 50:1 (1.3m/s) or 30:1 (2m/s).

Best of luck .

[bbot]

Thanks.
I've ordered the 50:1 Pololu HP motors. I'm building my ant by laminating fibreglass.The chassis is almost done, so far it looks good. It's hard and stiff as a rock!

[BeligerAnt]

If you are building a UK/European 150g ant, take care with the weight if using fibreglass.
Fibreglass is quite heavy. I have made ants with carbon fibre and kevlar shells, but had to use a seriously lightened chassis to stay within the weight limit.

[bbot]

If you are building a UK/European 150g ant, take care with the weight if using fibreglass.
Fibreglass is quite heavy. I have made ants with carbon fibre and kevlar shells, but had to use a seriously lightened chassis to stay within the weight limit.

Did you use premade sheets? I'm wondering, because I'm working with a balsa core... The chassis weighed just 6g (untreated). Now it's up to just 15g with two layers of 100g/m^2 fibre. And I reckon it's pretty tough, you would need to give it a full swing with a hammer to break it.

[BeligerAnt]

I moulded my own one-piece shells - probably more trouble than it's worth
It's not a hammer blow you have to worry about - a spinner disc will go straight through it (like a saw blade does). I resorted to laminating titanium and kevlar together Spinner-proof until the insides fell apart! Did take quite a while though...

[bbot]

Here's a mock up of my bot, I'm basically just waiting for the speed controllers to arrive...
Btw, I'm from Germany, so my plan is to enter the next MMM event!